FIG. 12 shows a general plug-type connector 5 provided with a conventional locating structure to ensure stable and firm plugging of the plug-type connector 5 in a corresponding receptacle 6. As shown, the plug-type connector 5 has a plug portion 51 forward extended from a front end thereof for plugging in an insertion hole 61 correspondingly provided in the receptacle 6 to form an electrical connection between them for signal transmission. A locating member 52 is pivotally assembled to a top of a main body of the plug-type connector 5. The locating member 52 has a rear end formed into a push portion 522 and a front end formed into at least one hook portion 521. A spring 523 is located between the push portion 522 and the main body of the plug-type connector 5. The hook portion 521 can be engaged with a locating recess 62 that is formed on the receptacle 6 at one side of the insertion hole 61, so as to ensure firm connection of the plug-type connector 5 to the receptacle 6 when the plug portion 51 is plugged in the insertion hole 61. When it is desired to disconnect the plug-type connector 5 from the receptacle 6, the push portion 522 of the locating member 52 is downward pushed to thereby raise the hook portion 521 at the front end of the locating member 52. At this point, the hook portion 521 is disengaged from the locating recess 62 of the receptacle 6, allowing the plug portion 51 to be unplugged from the insertion hole 61.
The above-described conventional plug-type connector 5 has relatively complicated structure. The height by which the hook portion 521 of the locating member 52 can be raised is in direct proportion to the depth by which the push portion 522 at the rear end can be pushed. Being limited by the requirement for miniaturized product, the push portion 522 of the locating member 52 could not be located at an increased height from the top of the main body of the plug-type connector 5, and the locating member 52 must have a thickness as small as possible. Therefore, the locating member 52 often has insufficient strength and tends to deform, and the hook portion 521 could not be exactly raised to a height corresponding to the downward pressed push portion 522. That is, the hook portion 521 might not be fully disengaged from the locating recess 62. On the other hand, the locating member 52 and the spring 523 are subject to deformation when a user applies an excessive force to the push portion 522, preventing the hook portion 521 from effectively engaging with the locating recess 62. Under this condition, the plug-type connector 5 could not be stably and firmly connected to the receptacle 6 when the plug portion 51 is plugged in the insertion hole 61.
It is therefore desirable and tried by the inventor to develop an improved plug-type connector that has simple structure and can be firmly connected to and easily disconnected from a receptacle.